Absorbent products such as paper towels, industrial wipers, baby wipers, diapers, food service wipers, feminine products, and other similar products are designed to include several important properties. For example, the products should have good bulk, a soft feel and should be highly absorbent. The products should also have good strength even when wet and should resist tearing. Further, for most applications, the products should have good stretch characteristics, should be abrasion resistant and should not deteriorate in the environment in which they are used.
In the past, many attempts have been made to enhance and increase certain physical properties of paper wiping products and other similar articles. Unfortunately, however, when steps are usually taken to increase one property of a wiping product, other characteristics of the product may be adversely affected. For instance, in pulp fiber based wiping products, softness can be increased by decreasing or reducing interfiber bonding within the paper web. Inhibiting or reducing fiber bonding, however, adversely affects the strength of the product. In fact, perhaps the most difficult and complex problem to solve in designing a paper wiping product is the ability to increase softness without decreasing strength.
One particular process that has proven to be very successful in producing paper towels and other wiping products is disclosed in U.S. Pat. No. 3,879,257 to Gentile, et al., which is incorporated herein by reference in its entirety. In Gentile, et al., a process is disclosed for producing soft, absorbent, single ply fibrous webs having a laminate-like structure.
The fibrous webs disclosed in Gentile, et al. are formed from an aqueous slurry of principally lignocellulosic fibers under conditions which reduce interfiber bonding. A bonding material, such as a latex elastomeric composition, is applied to at least one surface of the web in a spaced-apart pattern. The bonding material provides strength to the web and abrasion resistance to the surface.
Once the bonding material is applied to at least one side of the web, the web can be brought into contact with a creping surface. Specifically, the web will adhere to the creping surface according to the pattern by which the bonding material was applied. The web is then creped from the creping surface with a doctor blade. Creping the web mechanically debonds and disrupts the fibers within the web, thereby increasing the softness, absorbency, and bulk of the web.
In one alternative embodiment disclosed in Gentile, et al., both sides of the paper web are creped after the bonding material has been applied.
The processes disclosed in Gentile, et al. have provided great advancements in the art of making disposable wiping products. It would be desirable, however, if the softness of the paper products disclosed in Gentile, et al. could be increased without substantially compromising the strength of the products. It would also be very desirable if more cloth-like wiping products could be produced. As paper wiping products have evolved, the softness, look and feel of the paper products have become increasingly more important.
Specifically, one of the primary purposes of disposable paper wiping products is to serve as a substitute for various cloth and textile fabrics. As such, it is very desirable to be able to design a high strength paper wiping product that has a softness, look and feel that closely assimilates cloth.
Thus, there currently remains a need for a paper wiping product that closely assimilates the look and feel of cloth. A need also exists for a cloth-like paper wiping product that has improved softness over conventional products while still remaining strong. A need further exists for a cloth-like paper wiping product that does not become as compressed when wet as conventional products and therefore also has the feel of a cloth product during use.
A need also currently exists for an improved method of producing a base web made from pulp fibers, staple fibers, and mixtures thereof for use not only in various wiping products, but also in other products that are required to absorb fluids. In this regard, a need exists for a base web having improved absorbency and improved fluid pickup capabilities. A need further exists for an improved process for orienting fibers in the Z direction within a base web in order to improve absorbency and other various characteristics.